Sudan Academy of Sciences (SAS)

Atomic Energy Council

Code of Practice of Radiation Protection in Fixed Nuclear Gauges

A thesis for partial falfillment of master of science in

radiation and environment protection

BY: Mohammed Abbas Mohammed Eltayeb

Supervised by:

Dr. Isam Salih Mohamed

September 2012

Sudan Academy of Seienees (SAS)

Atomie Energy Counei؛

Code of Practice of Radiation Protection in Fixed Nuclear Gauges

BY

Mohammed Abbas Mohammed Eltayeb

Examination Committee

Title Name Signature

External Examiner Pro. Mohammed Osman Seed Ahamed

٢ , ٢٩ إ '٩

Supervisor Isam Salih Mohamedر خ ذ - .

September 2012

حيم الرحمن اش ر ال

ى ب ى ر ف ل م ز ك1ط

ق م اش صد ظي ع ال

رة لاية طه سو 14 ا

Acknowledgement

I would like to acknowledge and express my sincere

Thanks and deepest gratitude and appreciation to my family for

Their support and help and to every one

Helped me direct or indirect in this research

My sincere thanks to my supervisor

Dr. Isam Salih Mohammed

Above all, praise is to god for completing in research

؛ا

ة ص لا خ ل ا

ض ع هو البحث هذا من الغر ض ى العمل لقواعد مسودة و لاشعاع من الوقاية ف ى ا ف

س مجال ث النووية المقايي ل قواعد لاتتجاهل بحي عم صدارها تم التى ال 1998 عام ان ضم ت وتت صيا و مية الت عال حديثة ال ى ءوالهدف ال ى تقييم هو الثان ستو ن الم ه را وقاية ال لل

لاشعاع من ى ا ت من عدد ف س المستخدمة الشركا ى النووية للمقايي ق ف حقي ن.لت سودا الف غة تم الدراسة هذه اهدا عد مسودة صيا ل لقوا م ع ن مستمدة ال ت م صيا و مية الت عال و ال

لن ١١٩٨١١

سودة احتوت ى الم ضيع عل سة موا ة رئي رقاب شعا ال لا صادر عيةومخزنا المشعة م صيانة ال ب فحصن و ال ر س الت

ى الجانب عمل ت الدراسة لهذه ال ى اشتمل ت عل را ت من عدد الى علمية زيا الشركاسة هذه ءاوضحت ب الدرا ت من الكثير غيا ءا جرا ن ا لاما عية الوقاية و ا لاشعا فى ات ى قد مما المختلفة الشركا ود ض ي ع العاملين تعر عا لاث المبررم غير ل

خيرآ ت ا ضمن سة هذه ت ض الدرا ت بعت صيا ى من تحسن قد تنفذها تم اذا التى التو ستو مة وقاي ن ال ع م شعا ى ال ت ف ركا ش .ال

III

Abstract

The present work aims at developing and updating a code of practice of radiation protection in fixed nuclear gauges that comply with current international recommendations. The work also intended to evaluate the current radiation protection situation in two selected companies using nuclear gauges in Sudan. A draft ofthe code is proposed which includes the basic principle of protection such as source construction and gauges radiation monitoring, storage, maintenance and leak testing as well as specific issues related to nuclear gauges.

The practical part of this study included investigation of radiation protection in the companies using nuclear gauges for level detection, to evaluate thelevel of radiation protection and the compliance to the regulatory authorityتم ن"ئ ثمتااايار حآ - مم

The result revealed that the two companies do not have an effective radiation protection program and that can lead to exposure of workers to unnecessary doses. Some recommendations were stated, if implemented they could improve the status of radiation protection in those companies.

؛٧

Contents

. Chapter one

P r o d u c t i o n

Back groundأ

.2 Purpose ............................................................................................... 2

23 Scope

2. Chapter t w o .........................................................................................3

literature Review......................................................................................... 332.1 General

2.2 Radiation Protection in Nuclear Gauges...............................................4

Types of gauges............................................................................................ 4

2.3National efforts

3. Chapter three

Material and Method

73.1Matreials

3.2 Methods

4. Chapter four..............................................................................9

4.1 Results

4.2 Discussion............................................................................................ 10

4.3 Administrative requirements 2ل

4.4Source construction and gauge housing...............................................12

4.5 Management requirements.....................................................................13

V

4.6Warning notices....................................................................................٧

4.7 Radiation monitoring.........................................................................14

4.8 Storage and source accountancy....................................................... 15

4.9 Maintenance and leak testing............................................................. 16

4.10 Dealing with emergencies...............................................................16

4.11 End-of-life considerations............................................................... 17

4-12 local rules..........................................................................................17

Conclusion and Recommendation......................................................... 19

References................................................................................................ 20

Appendix 1..............................................................................................21

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND

Industrial gauges, which include sources o f ionizing radiation, are used for a variety o f

manufacturing process and quality control applications. These applications may include

the non-invasive measurement and control o f the thickness, level, density, weight,

composition or moisture content in an industrial production process. In each case, the

principle o f operation o f the gauge depends on the detection o f radiation that is

transmitted through, scattered by or emitted as a secondary emission from within, the

item or material o f interest. If the radiation sources used in fixed radiation gauges were

not adequately shielded, the dose rates near them would generally he o f a level that could

constitute a significant health hazard.

There are many industrial processes being controlled by fixed radiation gauges and there

is a wide range o f establishments in which they are used. These gauges may be located in

areas that are occupied by, adjacent to or remote from, employees or other individuals.

From time to time it may be necessary for maintenance personnel to have access to these

gauges or to the equipment on which they are mounted.

Radioactive sources are used in most fixed radiation gauges, although some gauges use

-ray tube and generator assemblies. A fixed radiation gauge can also incorporate an X-

ray tube and external power supply to energies the tube and generate X-rays. The

production o f X-rays by use o f an X-ray tube does not involve the use o f a radioactive

material.

Neutron generator tubes may also be used in some gauging applications. A neutron

generator tube may incorporate both radioactive tritium and an electrically energized tube

insert. A neutron generator tube gauge will therefore have aspects o f a gauge containing

a radioactive source and a gauge containing an electrically energized tube (ة )

1

This code applies to industrial radiation gauges that are designed for installation as a

fixed component within an industrial process and are used for the direct or indirect

control o f any part o f that process. They are commonly installed at fixed locations within

the industrial production process and will he referred to as fixed radiation gauges.

Although designed to he installed at fixed locations, this does not preclude them from

being mounted on structures which themselves move or have component parts that are

designed to move during the normal operation o f the gauge. The term ‘fixed radiation

gauge’ covers the whole o f the device and includes the radiation source (radioactive

material, energized X-ray tube or neutron generator tube), source containment

1.2 SCOPE

(radioactive source container, X-ray tube housing or shielded enclosure or neutron

generator tube housing or shielded enclosure), associated exposure controls and detector.

This Code refers, primarily, to fixed radiation gauges that are past the prototype or

development stage and are being produced in significant numbers with little or no design

variation. Gauges that are under development or test should, as far as practicable, adhere

to the requirements o f this code.

1.30bjective

The purpose o f this work is developing a code in order to establish working practices,

procedures and protective measures and to ensure the security o f radioactive sources.

This will ensure that the dose limits specified are not exceeded in agreement ofradiation

protection principles

CHAPTER TWO

LITERATURE REVIEW

2.!General:-

There are $everal hundred thousand nucleonic eontrol systems (NCS) ه آ nuclear gauges

installed in industry all over the world. They have been widely used by various industries

to improve the quality o f product, optimize processes, save energy and materials. The

economic benefits have been amply demonstrated and recognized by industry. Looking at

trends in the industrialization process o f developing countries, there is evidence that NG

technology will continue to play an important role in industry for many years to come.

Nuclear gauges (NG) are defined here as: “Control by instrumental measurement and

analysis as based on the interaction between ionizing radiation and matter” .

Simple nucleonic gauges first began to be used in industry over forty years ago. Since

then, there has been a continuous expansion in their usage. The competition from

alternative methods shows that NG have survived and prospered in the past because o f

their superiority in certain areas to conventional methods. The success o f NG is due

primarily to the ability, conferred by their unique properties, to collect data, which cannot

be obtained by other investigative techniques (1)

Many NG are now commercially available from several manufacturers. The development

of supporting technologies such as compact electronics, fast computers, high-resolution

detectors, small reliable neutron tubes, and dedicated computer modeling codes has

resulted in increased technical viability and economic acceptability o f NG . The

development o f th e next generation ofnucleonic devices is still taking place.

Relevant target areas are defined in international priority industrial sectors, such as oil

and gas production, mining and mineral ore processing, environmental monitoring, paper

and plastics industries, cement and civil engineering industries, where the benefit is

enormous and the technology competes well with conventional techniques.(ئ)

Internationally there are some countries deeloped their own code of praetiee in nuclear gauges

and o the^actices related to radiation, for example Australia, the Australian Radiation Protection

and Nuclear Safety Agency (ARPANSA) published code of practices and Radiation Protection

Serie$ to promote practices related to radiation including nuclear gauges and to protect human

health and the environment from the possible harmful effects in practices related to radiation.

2.2 Types of gauges

There are basically three main categ©ries ofnucleonic gauges used in industry:

Transmission gauges, used to measure density, thickness, etc. The source housing and

the detector are on opposite sides o f th e material and the radiation Is attenuated as it

travels through the material. Typical beta source activity ranges from 40 MBq to40 GBq

whilst gamma sources activities are between 0 .4 -40 GBq. X ray generators may also be

used.

Backscatter gauges, used to measure thickness o f coatings, well logging, etc. The

detector and source housing are on the same side o f th e material and therefore the

detector has to be shielded from the primary radiation. The radiation enters the material,

interacts with it and scatters back out. Typical beta souree activities usually range from

40-200 MBq whilst gamma sources are up to 100 GBq.

Reactive gauges (e.g. used for elemental analysis). Certain low energy gamma and X ray

sources can cause fluorescent X ray emissions in the material being investigated.

Typical souree activities range from 200 M B q - 4 0 GBq. X ray and neutron generators

may also be used رو).

Table 2.1 shows radioactive sources typically used in nuclear gauges.

Radioisotope Type ofradiation

?romethium -147 Beta

Thallium-204 Beta

Krypton-85 Beta

Strontium /¥ ttrium -90 Beta

Americium-241 Gamma

Caesium-137 Ciamma

Cobalt-60 Gamma

Neutron

NeutronCf-252

2.3 Radiation Protection in Nuclear gauges:-

Ionizing radiation can be very hazardous to humans and steps must be taken to

minimize the risks. This Section provides only a brief summary o f some o f the

principles o f radiation protection associated with the use o f sources o f ionizing

The primary aim o f radiation protection and safety is to provide appropriate standards

of protection and safety for people without unduly limiting the benefits o f practice

that gives rise to exposure.

٠٠٠ Protection ob jective : to prevent the occurrence o f deterministic effects in

individuals by keeping dose limit below the relevant threshold and to ensure that all

reasonable steps are taken to reduce the occurrence o f stochastic effects in

population at present and in future.

•> Safety objective: to protect individuals, society and the en\'ironment from harm by

establishing and maintaining effective defenses against radiological hazard.

Principle of rad ia tion pro tection :

ا Justification

no application ofradiation should be undertaken unless justified,

11. optimization o f pro tection

all doses should be kept “as low as reasonably achievable” (ALARA), economic and

social factors being taken into account,

radiation used in nucleonic gauges.(2)

FIT. ٨ ٨ ^ limitation

The dose limits for workers and the public are given below, although doses to gauge

^cr^ to rs are expected to be significantly below these levels during normal

operations.

occupationai exposuce should not ؛'؛٠٨١• The BSS specifies that doses to individuals

:exceed

an effective dose o ؛٨ f 20 mSv per year averaged over 5years not more than50 mSv

,any single year

an equivalent dose to the lens o f the eye o f 150 mSv.

an equivalent dose ،0 the extremities (hands or feet) or the skin o f5 0 0 mSv in a year.

•(2)

♦> Public dose limits:

]f the use o f nucleonic gauges may lead to the public being exposed, then the

following dose limits must not be exceeded.

an effective dose o f 1 mSv in a year.

an equivalent dose to the lens o f th e ye o f 15 mSv in a year

an equivalent dose to the skin o f 50 mSv.(2)

CHAPTER THREE

MATERIAL AND METHOD

3.1 Materials:-

Inspection check list (standard inspection check list developed by the regulatory

authority o f th e Sudan).

Rados universal gamma survey meter,

Specifications:

Dose rate: 0 .05^Sv /h - lOSv/h

Dose: O .O l^ S v - lO S v

Serial number: 260048

In odei'to carryout the investigation, two companies (And B) involved in the practice were

Selected because they use nuclear gauges for level detection.

The following materials are used in nuclear gauges in a selected company (A):-

Radioactive materials Specifications:

These are g au g es source (check mat instruments. Gamma ؛■ource Am-7.41)

7'he instruments are all imported from German;/.

The instruments are imported in different years, the activities showed below from the

manufacture.

Table 3 .1: shows the sources used in the company A and their specifications

No Source Activity in Physical Serial category

GB at state No

manufacturing O f th e

.source

ا Americium-241 1.67 solid 0987CW٠

4

2 Americium-241 1-67 solid 3017CW 4

3 Americium-241 1.67 solid 3019CW 4

4ا

Americium-241ا

1-67 solid 5465AR 4

The company does not have any survey meters to check the radiation around the

sources.

The following materials used in nuclear gauges in a second company (B):-

Radioactive materials Specifications

These are gauges source (check mat instruments. Gamma source Am-241).

The instruments are all imported from German.

The instruments are imported in different years, the activities showed below from the

manufacture.

Table 3.2: shows the sources used in the company B and their specifications

No Source Activity in

GB at

manufacturing

Physical

state

Serial No

O f th e

source

category

أ Americium-2411

أ 67 solid 1168CW 4

2 Americium-241 ١ 67 solid 0925AR 4ا

3 Americium-241 ا 67 solid 0986CW 4 ا

4 Americium-241 1-67 solid 1174CW 4

5 Americium-241 1.67 solid 2107AR 4

6

Americium-241 1.67 solid 5463AR 4

7 Americium-241 1.67 إ solid 5464AR 4ا

In the two companies above inspection list (standard inspection checklist developed b>

the regulatory authority o f Sudan) were used to evaluate radiation protection

3.2 Methods:-Visit to two companies using nuclcar gauges.

The visit included evaluation ofradiation levels around premises and the production

lines where the sources are fixed.

Collecting data and making comparison with radiation protection principle.

3.3 Study area:-The two companies using technology o f nuclear gauges are located in Khartoum and

work locations in Omdurman and Khartoum Bahri.

CHAPTER FOUR

RESULT AND DISCUSSION

4.1 R esu lts :-

• The study comprises both questionnaire and experimental measurements for each

company. In general both eompanies were not fully complying with the

requirement o f radiation protection, the dose rate at 30 centimeter from the

sources was bout back ground radioactivity, and the table below shows the results

of dose rate on the surface o f th e sources (check mat instruments).

• The following s table hows the results ofradiation surveying in the factory o f

company A.

Table 4.1 shows the dose rates on the surfaces o f th e sources in the factory o f

company A and the dose rate at 1 meter from each source is around the back ground

No Source Serial No

O f th e source

Dose rate o f gamma r a y s

1 Americium-241 0987CW 0.12 pSv/h

2 Americium -241 3017CW pSv/h ؤ 0.1

3 Americium -241 3019CW 0.22 pSv/h

4 Americium -241 5465AR 0.40 pSv/h

All these reading have been taken on the surface o f th e sources.

The instrument used in radiation survey Rados universal survey meter

The result o f th e questionnaire for company A as the following

R E C E IP T AND T R A N S F E R O F R A D IA T IO N SO U R C E S

No

Radioactive package opening procedures established and followed?

10

✓Incoming radioactive packages surveyed for damage, dose rates and potential

radioactive contamination before opening?

Satisfactory procedures are in place for the disposal o f radiation sources that

are no longer required, e.g. disposal only to authorized persons; notification إ

to the Regulatory Authority, etc.?

Records ofpackaging surveys, source receipt and transfer maintained?

W A R N IN G S IG N S AND L A B E L IN G2.

No

✓

✓

Yes

Controlled areas have appropriate warning signs (in the local language)?

Gauges housings are properly labeled (hazard warning in the local

language)?

Notices to workers are displayed in the local language?

N O T IF IC A T IO N S AND R E P O R T S3.

٠٠٠٠٠

٠

٠٠٠٠٠

Yes إ No

Have any program changes been implemented that required (but have not مreceived) approval by the Regulatory Authority?

ر?any notifiable incidents or accidents occurred since the last inspection 'ا ا 11؛آ ٠ ✓

If yes, have they been reported to the Regulatory Authority? {If no,؛ا

i

(accidents in Comments ٠٢ list the incidents أ

4 .TRAIN ING AND IN S T R U C T IO N O F W O R K E R S

No

ر

ر

٩/

٠ ٠ ٣ ٠ ٠ ٠

Yes

ر

Is basic radiation safety training p إ rodded to all persons who may be required

to work in the vicinity o إ f a gauge?s

١$ more advanced training given to personnel whose tasks require them to

install ©r work in close proximity to a gauge or where there is the potential

for exposure to the useful radiation beam (e.g. during maintenance inside

bins or hoppers fitted with level gauges)?

For in stream analysis gauges, are workers responsible for replacing إ

?protective source windows provided with special training أ

Refresher radiation safety training is provided periodically?

Do interviews with workers demonstrate an adequate level o إ f understanding

?regarding safety and emergency procedures إ

Discussion with the RPO إ demonstrates an appropriate knowledge o f th e

Regulatory Authority, the authorization, the legislation, conditions, safe إ

?working procedures, etc إ

Does the RPO have appropriate resources (time, personnel) and authority (to

take independent action to remedy urgent safety issues) to properly perform

the role?

Is staffing appropriate tor the radiation workers to discharge assigned duties

safely?

5 .RA D IA TIO N S O U R C E S

Yes No

ك إNuclides, chemical form, activities and uses as authorized in the license i.e

inventory confirmed? (Also confirm inventory for x-ray gauges)

12

ر '

✓

Leakage tests performed on sealed sources (other thar، in stream analysis

gauges)?

For in stream analysis gauges, is the source protective window routinely

checked for contamination by an approved method when replaced?

Records o f leakage tests and inventory maintained?

6 .PERSONNEL R A D IA T IO N M O N IT O R IN G

No

V

ر

ر

١/

ص

•٦

.ل

ر

Yes

. .د.

T

Licensee provides personal dosimeters to all radiation workers?

Dosimetry supplier is an authorized provider?

Name o f provider

Dosimeters provided are appropriate for the radiation type and energy

Dosimeters are exchanged at the prescribed period?

Dosimetry reports are promptly reviewed by the RPC?

Is it evident that personal dosimeters are being worn by workers?

Individual workers are informed o f their monitoring results when each

monitoring report is received (regardless o f th e dose measured)?

Does the licensee apply ALARA to occupational exposure?

Personnel monitoring records are maintained?

toInspector reviewed personnel monitoring records for the period from

fhe table shows the results o f radiation surveying in the factory o f company B

fable 4.2 shows the dose rates on the surfaces o f th e sources in the factory o f

Company B and the dose rate at 1 meter from each source is around the back ground

Dose rate o f

O f th e source gamma

1 Americium-241 1168CW 0.43 uSv/h

2 Americium-241 0925AR 0.36 |LiSv/h

اAmericium-241 0986CW 0.21 fiSv/h

4

Americium-241 1174CW 0.32 f-iSv/h

Americium-241 2107AR 0.22 uSv/h

6

Americium-241 5463AR 0.20 |iSv/h

7 Americium-241 5464AR aSv/h0.20 ؛

All these reading have been taken on the surfaee ©f the sources.

The instrument used in radiati©n survey is Rados universal survey meter

The result o f th e questionnaire for companyB as the following

NoYes

R E C E IP T AND T R A N S F E R O F R A D IA T IO N SO U R C E S4.

?Radi©ac،ive paekage opening procedures established and followed إ٠

٠

Ineoming radioactive packages surveyed for damage, dose rates and potential ؛٠

?radioactive contamination before opening إ

Satisfactory procedures are in place for the disposal ofradiation sources that

are no longer required, e.g. disposal only to authorized persons; notification

to the Regulatory Authority, etc.?

Records o f packaging surveys, source receipt and transfer maintained?

W A R N IN G S IG N S AND L A B E L IN G

Yes No

?Controlled areas have appropriate warning signs (in the local language)ب

14

Gauges housings are properly labeled (hazard warning in the local

language)?

Notices to workers are displayed in the local language?

6. N O T IF IC A T IO N S AND R E P O R T S

Have any program changes been implemented that required (but have not

received) approval by the Regulatory Authority?

Have any notifiable incidents or accidents occurred since the last inspection? إ

If yes, have they been reported to the Regulatory Authority? (.I fn o ,

list the incidents or accidents in Comments)

4 .TR A IN IN G AND IN S T R U C T IO N O F W O R K E R S

Is basic radiation safety training provided to all persons who may be required

to work in the vicinity o f a gau

more advanced training given to personnel whose tasks require them to 1؟

install or work in close proximity to a gauge or where there is the potential

for exposure to the useful radiation beam (e.g. during maintenance inside

(?bins or hoppers fitted with level gauges

For in stream analysis gauges, are workers responsible for replacing

protective souree windows provided with special training?

Refresher radiation safety training is provided ^ r io d ica l jy?

■١

كم

■/

•/

كم

✓

Are training records maintained ٢٥٢ each worker?

□ ه interviews with workers demonstrate an adequate level o f understanding م

regarding safety and emergency procedures?

Discussion with the RPO demonstrates an appropriate knowledge o f th e

Regulatory Authority, the authorization, the legislation, conditions, safe

working procedures, etc?

Does the RPO have appropriate resources (time, personnel) and authority (to إ ا ^

take independent action to remedy urgent safety issues) to properly perform إ

the role? ا

Is staffing appropriate for the radiation workers to discharge assigned duties

safely?

5 .R A D IA TIO N S O U R C E S

Yes No

-/ .Nuclides, chemical form, activities and uses as authorized in the license i.e؛

inventory confirmed? (Also confirm inventory for x-ray gauges)

Leakage tests perfo]*med on sealed sources (other than in stream analysis إ ^

gauges)? أ

For in stream analysis gauges, is the source protective window routinely إ

checked for contamination by an approved method when replaced?

Records o f leakage tests and inventory maintained?

6 .P E R S O N N E L R A D IA T IO N M O N IT O R IN G

Yes No

Licensee provides personal dosimeters to all radiation workers?

Dosimetry supplier is an authorized provider?

Nam e ofprov ider

Dosimetecs provided are appropriate for the radiation type and energy?

✓

٩/

✓

✓

?Dosimeters are exehanged at the prescribed period إ

?Dosimetry reports are promptly reviewed by the RPO أ

Is it evident that personal dosimeters are being worn by workers?

Individual workers are informed o fthe ir monitoring results when each

monitoring report is received (regardless o f th e dose measured)?

Does the licensee apply ALARA to occupational exposure?

Personnel monitoring records are maintained?

Inspector reviewed personnel monitoring records for the period from

4.2D s؛ c u s s o؛ n : -

This study has been conducted at two companies using nuclear gauges in Sudan, The

evaluation o f radiation protection took place by conducting mission to the two

companies using questionnaire that cover all areas o f radiation protection that are

mentioned in this code .

? ١١٠ general results o f the questionnaire showed that the two companies do not

comply entirely with some issues indicated in this code, fire protection measures are

not adequate, records o f leakage tests are not existed, warning signs, stickers, and

labeling are not used on the sources, controlled area and supervised area are not

demarcated, there are no written emergency plan, and the two companies do not have

area monitoring devices.

The national code o f practice issued by SAEC in 1998 was for general use o f ionizing

radiation , thus for all those above non compliance in radiation protection in the two

companies ,there was need to develop code o f practice in nuclear gauges based on

national and international recommendations. The following presents development o f

the code.

17

The draft ofthe eode of radiation protection

4.3 Am inistrative requirements

A uthorization

In order to control the use ofradiation sources and to ensure that the operating

organization meets the requirements o f th e safety standards, the legal person responsible

for any radiation source will need to apply for an authorization from the national

Regulatory Authority. This authorization is usually in the form o f a license 0،•

registration. Prior to buying or acquiring a nucleonic gauging system, the operating

organization will, therefore, need to apply for such an authorization from the regulatory

authority. The regulatory authority will need details about the gauging equipment, such

as: the purpose for which it will be used, the radionuclide(s) and activity, manufacturer

and model, details o f th e storage facility and installation site, copies o f approval

certificates, end o f life considerations (disposal or return to supplier) etc.

The regulatory Authority will also need: information regarding the people

who will be using the equipment, such as their qualifications and training in radiation

safety etc .Further details about the relevant legal and governmental infrastructure,

the regulatory control o f sources, and the notification and authorization for the possession

and use ofradiation sources are available from IAEA.(2)

Inspection an d en fo reem en t

The Regulatory Authority may inspect the re^strant/licensee to audit their provisions for

radiation safety and to physically inspect the premises. Enforcement action may be taken

against the operating organization if the level ofradiation protection and safety are

considered unacceptable

4.4Souree e©nstruetion and gauge housing

Sources need to be designed, manufactured and tested to meet the requirements o f th e

appropriate ISO standard or equivalent national standard. Sources also should have been

leak-tested in accordance with the appropriate ISO standard and have a valid leak-test

certificate.

18

The minimum test requirements include high and i©w temperature tests for normal use

and an elevated temperature test for accident conditions. Levels o f leakage

radiation are measured on and around the gauge for both the beam ‘O N ’ and ‘O FF’

condition to ensur،؛ safety o f th e persons working in the vicinity. A vibration test is also

performed on a gauge that intended to be used in locations where there is likelihood o f

mechanical vibrations. (5)

4.5Management requirements

The operating organization has the ultimate responsibility for ensuring that gauges are

used in compliance with the relevant national regulations. This responsibility cannot be

delegated to employees, workers, the radiation protection officer (RPO), the qualified

expert or anyone else. An effective management safety infrastructure is therefore

necessary to ensure that a high standard o f radiation protection and safety is maintained.

Some organizations may need to consult qualified Experts for advice on specific areas o f

radiation protection (e.g. which radiation monitors to use). The scope and role o f these

experts should be clearly defined. Quality assurance programs should ensure that

radiation protection and safety measures within the organization continue to be effective.

Supervision

In order to provide adequate supervision ofprotection and safety to ensure the local rules

are obeyed, operating organizations will need to appoint a radiation protection

officer (RFO). M anagement should ensure that the RFO is delegated the appropriate

authority to ensure that operating procedures and local rules are followed. The RPO

should also have the authority to stop any working practices they consider unsafe.

Q uality a ssu ran e e

Assurance that radiation protection and safety requirements are being satisfied should be

achieved through formal quality control mechanisms and procedures for reviewing and

assessing the overall effectiveness ofprotection and safety measures. Systematic audits

and reviews should detect and result in correction o f system$ that do not function.

4.6 Warning notices

All radiation sources should display the radiation trefoil to warn o f th e potential hazard.

Details o f th e radionuclide, activity on a specified date and serial number should be

included on a label permanently attached to the source housing. Any shutters should be

clearly marked to indicate the status o f th e source to persons in the vicinity. X ray

equipment should also display a clear indication when radiation is being generated.

Notices should s*tate whether any controlled areas are designated around the gauge.

4.7 Radiation monitoring

Operating organizations need to have in place an effective program for monitoring

occupational exposure to radiation. Guidance on establishing a monitoring program for

external exposure, the appropriate dosimetry to be used for workplace and individual

monitoring and record keeping is given in an IAEA Safety Guide

W o rk p lace m o n ito rin g

Portable dose rate monitors can be used to measure radiation levels (normally in

microsieverts or millisieverts per hour) around gauges. Monitoring may be carried

out for several reasons, for example to;

٠ c h e c l ^ e h i e l d i n ^ o u n d a ٣ ٧ ٣ is intact

٠ check a shutter is closed before carrying out maintenance on or close to a gauge

٠ check the radiation levels around a shipping container to ensure it is safe to transport

٠ confirm the extent o f a controlled area around a gauge

٠ check the shielding around a source storage facility is acceptable.

There are many different types o f radiation monitor and it is important to ensure the

correct one is used otherwise incorrect assumptions may be made which could lead to

persons being inadvertently exposed, possibly to high levels o f radiation, ?o r example

special monitors are needed to detect neutron radiation, monitors used to detect gamma

radiation may not detect beta radiation. Persons carrying out monitoring should therefore

be trained, follow approved procedures and keep appropriate records o f th e radiation

levels measured. All monitors should be routinely calibrated (normally annually) by a

qualified Expert.(3)

P e rso n a l m on ito ring

The dose rate monitors discussed above can be used to indirectly estimate the radiation

dose to a person who works in the area where the measurement was made. In some

20

situation, however, workers may he required to wear personal dos meter$ to assess their؛

accumulated individual dose over a period o f time, perhaps because they are carrying out

maintenance on several gauges or perhaps are working with portable gauges.

There are several different types o f personal dosimeter that gauge users may encounter,

but they can be divided into categories: those that give a direct reading o f accumulated

dose and those that require processing by a laboratory (e.g. film badge or thermo

luminescent dosimeter (TLD)). The type o f dosimeter required and where/when it should

be worn will normally be advised by the radiation protection officer.(3)

4.8 Storage and souree aecountaney

StorageThere will be occasions when sources need to be stored. For example, gauges not in use,

gauges removed from a production line during maintenance, old gauges awaiting

disposal, etc. To ensure the safety and security o f th e sources the storage facilities should:

provide adequate shielding, (4)

• be physically secure (e.g. locked when not in use)

٠ not be used as a general storage area for other goods,

٠ be fire p roof and not contain other hazardous materials (e.g. flammable liquids) be

dry,

٠ appropriately labeled (e.g. radiation trefoil and warning notices in a local language).

Source accountancyRecords need to be kept which show the location o f each source at all times. National

regulations may specify how frequently the accountancy checks need to be carried out,

but in general, the following can be applied:

٠ sources in permanently installed gauges should be accounted for at least once per

month

sources in portable gauges should be acounte

and once a week when they are in storage (4)

21

4.9 Maintenance and !eak testing

Maintenance

Nucleonic gauges are often used in harsh environmental conditions which may result in

the radiation safety and protection o f th e gauge he adversely affected, for example;

shielding may be degraded, shutters may stick, warning notices may become illegible,

etc. It is therefore important that gauges are included in a routine maintenance schedule.

Persons carrying out the maintenance work need to be aware o f th e radiation hazards and

be appropriately trained. When working close to a gauge a radiation monitor should

always be used to confirm that any shutters are fully closed and that the source is fully

shielded.

Leak testing

When a new radioactive source is purchased it should be supplied with a certificate

confirming that it is free from contamination. Periodic re-checks need to be carried out by

an appropriately trained and qualified person to ensure that the structure o f th e source

remains intact. Gauges that are used under harsh environmental conditions (e.g. high

temperature, corrosive chemicals, and high levels o f vibration) may need to be checked

more frequently. The intervals for leak testing should not normally exceed 2 years (and

may be more frequent), but this will normally be specified by the regulatory authority

4.10 Deaiing with emergencies

Before first using any nucleonic gauge the operating organization should carry out an

assessment to identify any abnormal situations that may occur and to estimate the

magnitude o f th e occur hazard. Contingency plans should be prepared and rehearsed so

that ؛f a n accident does the plan can be quickly implemented to regain control o f th e

situation and therefore mitigate the consequences. Several accidents from the use o f

nucleonic gauges in industry have already occurred these were mainly due to the sharp,

unexpected rise o f temperature in the process causing the melting o f th e gauge and

source; and to the accidental loss during borehole logging. Special measures were taken

in these cases, isolating the area and temporarily closing the process line or the hole.

22

O ther examples ©f p©tent؛al accidents t© be c©ns؛dered are: l©st or st©len source, other

forms ofphysica l damage to the gauge (e.g. crushing), jam m ed shutter, transp©rt

accident, suspected ex^p©sure o f persons, leaking s©urce etc.(5)

4.11End-of-Iife considerations

M any accidents have occurred with disused ٠٢ abandoned sources. Before a source is

purchased, considerati©n needs to be given to what will happen t© the source when it is

no longer o fu se ٠٢ i f the ©perating organization goes bankrupt etc. In many cases the

preferred ©pti©n is t© return the s©urce t© the supplier, p©$sibiy f©r recycling. O ther

©^ti©ns include permanent disp©sal or long- term storage. All options have financial and

!©gistical c©nsequences that need t© be considered before the gauge is purchased.(3)

4.12 focal rules

Employees should follow the procedures specified in L©cal Rules t© ensure that an

adequate level o f protection and safety is maintained during normal daily w©rk

with the gauges and any maintenance on the gauges or ©ther equipment in the

proximity.

Regulati©ns ©f ؛©nizing radiati©n require written l©cal rules for every controlled area, and

where appropriate supervised area, these should identify the key working instructions

intended to restrict exposure to radiation. And the foll©wing p©ints are imp©rtant in the

local rules.

١. Department manager is responsible to set ™؛e$ for work connected with ionizing

radiation with in that department; this should be formulated in c©njuncti©n with

the radiati©n protecti©n ©fficer (R ? 0 ) and radiation pr©tecti©n supervisor (RPS).

2. In ©rder to be effective ,l©cal rules sh©uld be brief ,focused, clear and peri©dically

reviewed , and all members with staff with ionizing radiation should familiar and

have ready access to l©cal rules and other safety documents

3. Department m anager also is resp©nsible for taking all reasonable steps to ensure

that local rules are observed.

F o rm a t

23

The local rules should only include essential content and optional information where

appropriate.

E ssen tia l con ten t

• Identific^ ion and description o f designated areas

٠ Names o f RPOs

٠ Arrangement for restricting access.

• Dose investigation level.

٠ Summary o f working instruction including written arrangements for non-

classified person, in order to keep their doses as low as reasonable achievable.

• Contingency arrangements foreseeable accidents.

O p tio n a l co n ten t

• M anagement and supervision o f work.

• Testing and maintenance o f engineering safety feature, warning devices, etc

٠ Radiation and contamination monitoring.

• Testing o f monitoring equipment.

• Program to review if doses are being kept ALARA.

• P ro c e d u re for initiating investigation.

٠ Procedure for ensuring staff has information, instruction and training.

24

٠

The beneficial role o ؛٨ fnucleon ic gauge for process ©fcoritrol and optimization

industry is amply demonstrated and recognized .The nuclear gauge derives a benefit

to industry o f billion us dollars a year worldwide.

The nuclear gauges practice actually started in Sudan in about 2001 ,when several

companies o f gaseous water began to use this practice t© detect level automatically

instead o f manually to increase the production ,after that several companies insert this

service ,then the cement companies started to use N G for quality control processes

,then research institutes in all this period 2002 to 2012 there was not any specific

code o f practice in N G ju s t the code o f practice issued by SAEC in 1998 for general

use o f ionizing radiation ,thus this research has been made specifically for code o f

practice in nuclear gauges and it could be adopted, developed and improved by The

national authority

R e ^ m m e n d a t io n-:

The two companies that have been covered in this code have to do a lot to improve the

level o f safety to be updated with current regulations ,particularly regarding the follow

issues-:

Provide survey meters for routine check to make sure that there no leakage or

contamination

1. Availability o f a written emergency plan.

2. Establishing records o f worker doses.

.3. Incidents investigation records

Conclusion and recommendation:-Conclusion

25

m

R eferences :-

1. Technical data on nucleonic gauges IAEA -TECDOC-1459. IAEA, V IENNA,

second edition Printed by the IAEA in Austria July 2005

2. Safety series n o .I I5 international basic safety for protection against ionizing

radiation and the safety ofradiation sou rces .. IAEA, VIENNA,

3. Assessment o f occupational exposure due to external sources o f radiation (safety

guides no.rs.g.1.3 IAEA, VIENNA).

4. Code o f conduct on the safety and security o f radioactive sources (international

atomic energy commission VIENNA 2004) Printed by the IAEA in Austria

January 2004.

5. Code o f conduct on the safe use o f fixed radiation gauges. (Australian radiation

protection and nuclear safety agency). Approved by Australian Radiation Health

Committee 25-26 October 2006, and on 8 December 2006,

26

Inspection form

Sudan academy ofscience

M.sc Radiation and Environmental protection

Questionnaire

1. R E C E IP T AND T R A N S F E R O F R A D IA T IO N SO U R C E S

NoYes

Radioactive package opening procedures estabJished and followed?

Incoming radioactive packages surveyed for damage, dose rates and potential ر

?radioactive contamination before opening إ

Satisfactory procedures are in place for the disposal o أ f radiation sources that

are no longer required, e.g. disposal only to authorized persons; notification أ

?.to the Regulatory Authority, etc أ

Records o f packaging surveys, source receipt and transfer maintained?

2 .W A R N IN G S IG N S AND L A B E L IN G

NoYes

Controlled areas have appropriate warning signs (in the local language)?

Gauges housings are properly labeled (hazard warning in the local

language)?

?Notices to workers are displayed in the local language إ

3 .N O T IF IC A T IO N S AND KF .POKTS

Have any program changes been implemented that required (but have not إ

?received) approval by the Regulatory Authority إل —

Have any notifiable incidents or accidents occurred since the last inspection?

If yes, have they been reported to the Regulatory Authority? (.Ifno ,

list the incidents ٠٢ accidents in Comments)

No¥ e s

4.T R A IN IN G AND IN S T R U C T IO N O F W O R K E R S

Is basic radiation safety training provided to all persons who may be required إ٠

?the vicinity o f a gauge ؛١٦ to work إ

Is more advanced training given to personnel whose tasks require them to

install or work in close proximity to a gauge or where there is the potential

for exposure to the useful radiation beam (e.g. during maintenance inside

bins or hoppers fitted with level gauges)?

For in stream analysis gauges, are workers responsible for replacing إ

?protective source windows provided with special training إ

?Refresher radiation safety training is provided periodically إ

Are training records maintained for each worker?>٠٠

Do interviews with workers demonstrate an adequate level o f understanding

?regarding safety and emergency procedures إ

Discussion with the RPO demonstrates an appropriate knowledge o f th e

Regulatory Authority, the authorization, the legislation, conditions, safe

working procedures, etc?

Does the RPO إ have appropriate resourees (time, personnel) and authority (to

take independent action to remedy urgent safety issues) to properly perform إ

?the role أ

Is staffing appropriate for the radiation workers to diseharge assigned duties

safely?

NoYes

5 .R A D IA T IO N S O U R C E S

Nuclides, chemical form, activities and uses as authorized in the license i.e.

inventory confirmed? (Also confirm inventory for x-ray gauges)

Leakage tests performed on sealed sources (other than in stream analysis

gauges)?

Lor in stream analysis gauges, is the source protective window routinely

checked for contamination by an approved method when replaced?

Records o إ f leakage tests and inventory maintained?

.P E R S O N N E L R A D IA T IO N M O N IT O R IN G

Yes No

Licensee provides personal dosimeters to all radiation workers?

Dosimetry supplier is an authorized provider?

Nam e ofprov ider

Dosimeters provided are appropriate for the radiation type and energy?

Dosimeters are exchanged at the prescribed period?

Dosimetry reports are promptly reviewed by the RPO?

Is it evident that personal dosimeters are being worn by workers?

Individual workers are informed o fthe ir monitoring results when each

monitoring report is received (regardless o f th e dose measured)?

? ٩

Does the licensee apply ALARA to occupational exposure?٢

Personnel monitoring records are maintained?

Inspector reviewed personnel monitoring records for the period from